Disable or Enable USB Port on XP

To Disable

Open regedit from run command and goto the following path
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR]
Now in the right pane, double-click Start and type 4 in the Value data box (Hexadecimal) and quite the registry editor.
To enable

Change the Start value back to 3.

Regular Expression for Email in Perl

The following is a regular expression whic can be used to check a valid email.

^[a-z]+\d*[_.]*[a-z]*@[a-z]+\.(com|org|net|in|co\.in)$

This will check the following
1) Email should start with a letter.
2) There can be any digit or _ or . in between the username.
3) Should contain @ symbol after username.
4) After @ symbol it should have domain name
5) The allowed extensions are com,net,org,in,co.in

suggessions are welcome

Differences Between Server.Transfer and Response.Redirect

If you read a lot of industry magazines and ASP.NET code samples, you may find that, although the majority use Response.Redirect to send the user to another page, some seem to prefer the rather mysterious-sounding Server.Transfer. So, what's the difference?

Well, Response.Redirect simply sends a message down to the browser, telling it to move to another page. So, you may run code like:

Response.Redirect("WebForm2.aspx")
or

Response.Redirect("http://www.karlmoore.com/")
to send the user to another page.

Server.Transfer is similar in that it sends the user to another page with a statement such as Server.Transfer("WebForm2.aspx"). However, the statement has a number of distinct advantages and disadvantages.

Firstly, transferring to another page using Server.Transfer conserves server resources. Instead of telling the browser to redirect, it simply changes the "focus" on the Web server and transfers the request. This means you don't get quite as many HTTP requests coming through, which therefore eases the pressure on your Web server and makes your applications run faster.

But watch out: because the "transfer" process can work on only those sites running on the server, you can't use Server.Transfer to send the user to an external site. Only Response.Redirect can do that.

Secondly, Server.Transfer maintains the original URL in the browser. This can really help streamline data entry techniques, although it may make for confusion when debugging.

That's not all: The Server.Transfer method also has a second parameter—"preserveForm". If you set this to True, using a statement such as Server.Transfer("WebForm2.aspx", True), the existing query string and any form variables will still be available to the page you are transferring to.

For example, if your WebForm1.aspx has a TextBox control called TextBox1 and you transferred to WebForm2.aspx with the preserveForm parameter set to True, you'd be able to retrieve the value of the original page TextBox control by referencing Request.Form("TextBox1").

This technique is great for wizard-style input forms split over multiple pages. But there's another thing you'll want to watch out for when using the preserveForm parameter. ASP.NET has a bug whereby, in certain situations, an error will occur when attempting to transfer the form and query string values. You'll find this documented at http://support.microsoft.com/default.aspx?id=kb;en-us;Q316920.

The unofficial solution is to set the enableViewStateMac property to True on the page you'll be transferring to, then set it back to False. This records that you want a definitive False value for this property and resolves the bug.

So, in brief: Response.Redirect simply tells the browser to visit another page. Server.Transfer helps reduce server requests, keeps the URL the same and, with a little bug-bashing, allows you to transfer the query string and form variables.

Temporarily Save Data in a Datatable Before Inserting Or Updating into SQL SERVER Database.

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

namespace TestApp
{
public partial class dt : System.Web.UI.Page
{
DataTable dt1 = new DataTable();
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
SqlConnection cn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings
["empConnectionString"].ToString());
SqlDataAdapter da = new SqlDataAdapter("select * from emp", cn);
DataSet ds = new DataSet();
da.Fill(ds);
cn.Close();
createDataTable();
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
DataRow dr = dt1.NewRow();
string fdf = ds.Tables[0].Rows[i][0].ToString();
dr["empno"] = ds.Tables[0].Rows[i][0].ToString();
dr["ename"] = ds.Tables[0].Rows[i][1].ToString();
dr["address"] = ds.Tables[0].Rows[i][2].ToString();
dr["city"] = ds.Tables[0].Rows[i][3].ToString();
dr["state"] = ds.Tables[0].Rows[i][4].ToString();
dr["zip"] = ds.Tables[0].Rows[i][5].ToString();
dr["upd"] = "0";
dr["nc"] = "0";
dt1.Rows.Add(dr);
}
dg1.DataSource = dt1;
dg1.DataBind();
dt1.AcceptChanges();
dt1.GetChanges();
this.ViewState.Add("table", dt1);
}
}
protected void dg1_ItemCommand(object source, DataGridCommandEventArgs e)
{
hidindex.Value = e.Item.ItemIndex.ToString();
if (e.CommandName == "edit")
{
TextBox1.Text = e.Item.Cells[1].Text.ToString();
TextBox2.Text = e.Item.Cells[2].Text.ToString();
TextBox3.Text = e.Item.Cells[3].Text.ToString();
TextBox4.Text = e.Item.Cells[4].Text.ToString();
TextBox5.Text = e.Item.Cells[5].Text.ToString();
}
}
protected void btnedit_Click(object sender, EventArgs e)
{
int ind = int.Parse(hidindex.Value.ToString());
dt1 = (DataTable)(this.ViewState["table"]);
DataRow dr = dt1.NewRow();
dr["ename"] = TextBox1.Text;
dr["address"] = TextBox2.Text;
dr["city"] = TextBox3.Text;
dr["state"] = TextBox4.Text;
dr["zip"] = TextBox5.Text;
dr["upd"] = "1";
dr["nc"] = "0";
dr["empno"] = dt1.Rows[ind]["empno"].ToString();
dt1.Rows.RemoveAt(ind);
dt1.Rows.InsertAt(dr, ind);
dt1.AcceptChanges();
dt1.GetChanges();
dg1.DataSource = dt1;
dg1.DataBind();
TextBox1.Text = "";
TextBox2.Text = "";
TextBox3.Text = "";
TextBox4.Text = "";
TextBox5.Text = "";
}
protected void Button1_Click(object sender, EventArgs e)
{
dt1 = (DataTable)(this.ViewState["table"]);
DataRow dr = dt1.NewRow();
dr["ename"] = TextBox1.Text;
dr["address"] = TextBox2.Text;
dr["city"] = TextBox3.Text;
dr["state"] = TextBox4.Text;
dr["zip"] = TextBox5.Text;
dr["upd"] = "0";
dr["nc"] = "1";
dt1.Rows.Add(dr);
dt1.AcceptChanges();
dt1.GetChanges();
dg1.DataSource = dt1;
dg1.DataBind();
}
protected void Button2_Click(object sender, EventArgs e)
{
SqlConnection cn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings
["empConnectionString"].ToString());
dt1 = (DataTable)(ViewState["table"]);
for (int i = 0; i < dt1.Rows.Count; i++)
{
string no = dt1.Rows[i]["empno"].ToString();
string st = dt1.Rows[i]["nc"].ToString();
if (dt1.Rows[i]["nc"].ToString() == "1")
{
SqlCommand cmd = new SqlCommand("insert into emp(ename,address,city,state,zip) values(@ename,@address,@city,@state,@zip)", cn);
SqlParameter p1 = new SqlParameter("@ename", SqlDbType.VarChar, 50);
p1.Value = dt1.Rows[i]["ename"].ToString();
cmd.Parameters.Add(p1);
SqlParameter p2 = new SqlParameter("@address", SqlDbType.VarChar, 50);
p2.Value = dt1.Rows[i]["address"].ToString();
cmd.Parameters.Add(p2);
SqlParameter p3 = new SqlParameter("@city", SqlDbType.VarChar, 50);
p3.Value = dt1.Rows[i]["city"].ToString();
cmd.Parameters.Add(p3);
SqlParameter p4 = new SqlParameter("@state", SqlDbType.VarChar, 50);
p4.Value = dt1.Rows[i]["state"].ToString();
cmd.Parameters.Add(p4);
SqlParameter p5 = new SqlParameter("@zip", SqlDbType.Int);
p5.Value = int.Parse(dt1.Rows[i]["zip"].ToString());
cmd.Parameters.Add(p5);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}
if (dt1.Rows[i]["upd"].ToString() == "1" && dt1.Rows[i]["nc"].ToString() == "0")
{
SqlCommand cmd = new SqlCommand("update emp set ename=@ename,address=@address,city=@city,state=@state,zip=@zip where empno=@empno", cn);
string sdf = dg1.DataKeys[0].ToString();
string ddd = dt1.Rows[i]["empno"].ToString();
SqlParameter p1 = new SqlParameter("@ename", SqlDbType.VarChar, 50);
p1.Value = dt1.Rows[i]["ename"].ToString();
cmd.Parameters.Add(p1);
SqlParameter p2 = new SqlParameter("@address", SqlDbType.VarChar, 50);
p2.Value = dt1.Rows[i]["address"].ToString();
cmd.Parameters.Add(p2);
SqlParameter p3 = new SqlParameter("@city", SqlDbType.VarChar, 50);
p3.Value = dt1.Rows[i]["city"].ToString();
cmd.Parameters.Add(p3);
SqlParameter p4 = new SqlParameter("@state", SqlDbType.VarChar, 50);
p4.Value = dt1.Rows[i]["state"].ToString();
cmd.Parameters.Add(p4);
SqlParameter p5 = new SqlParameter("@zip", SqlDbType.Int);
p5.Value = int.Parse(dt1.Rows[i]["zip"].ToString());
cmd.Parameters.Add(p5);
SqlParameter p6 = new SqlParameter("@empno", SqlDbType.Int);
p6.Value = int.Parse(dt1.Rows[i]["empno"].ToString());
cmd.Parameters.Add(p6);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}
}
}
protected void createDataTable()
{
DataColumn c0 = new DataColumn("empno",typeof (Int32));
DataColumn c1 = new DataColumn("ename",typeof (string));
DataColumn c2 = new DataColumn("address");
DataColumn c3 = new DataColumn("city");
DataColumn c4 = new DataColumn("state");
DataColumn c5 = new DataColumn("zip");
DataColumn c6 = new DataColumn("upd");
DataColumn c7 = new DataColumn("nc");
dt1.Columns.Add(c0);
dt1.Columns.Add(c1);
dt1.Columns.Add(c2);
dt1.Columns.Add(c3);
dt1.Columns.Add(c4);
dt1.Columns.Add(c5);
dt1.Columns.Add(c6);
dt1.Columns.Add(c7);
}
}
}